Flexible pyrotechnic relay

ABSTRACT

A flexible pyrotechnic relay includes a spiral-wound wire tube covered by a flexible plastic sheath and having an initiating explosive charge adjacent one end thereof, one or more explosive relay charges spaced along the interior thereof, and a flame sensitive receptor charge adjacent the other end thereof. The detonation of the initiating charge is propagated by the relays along the tube to fire the flame sensitive primer.

nited States Patent 1191 Plumer Feb. 19, 1974 [54] FLEXIBLE PYROTECHNIC RELAY 3,382,802 5/1968 Prior et a1 102/27 3,447,464 6/1969 Menichelli et al. 102/70 [75] Invenmr- Plume" Santa Barbara 3,590,739 7 1971 Persson 102 27 Cahf' 3,296,968 1/1967 Shulman et al 102/27 [73] Assignee: General Motors Corporation,

Detroit, Mich Primary Examiner-Verlm R. Pendegrass Attorney, Agent, or Firm-Herbert Furman [22] Filed: Mar. 31, 1972 [21] App]. No.: 239,948 [57] ABSTRACT A flexible pyrotechnic relay includes a spiral-wound 52 us. c1. 102/27 R, 102/70 R Wire tube covered y a flexible Plastic sheath and [51] Int. Cl. C06c 5/00 ing initiating explosive charge adjacent one end [58] Field of Search 102/27, 70 thereof one or more explosive relay charges Spaced along the interior thereof, and a flame sensitive recep- [56 R f r Ci tor charge adjacent the other end thereof. The detona- UNITED STATES PATENTS tion of the initiating charge is propagated by the relays along the tube to fire the flame sensitive primer. 3,027,839 4/1962 Grandy et a]... 102/27 3,311,056 3/1967 Noddin 102/27 4 Claims, 2 Drawing Figures FLEXIBLE PYROTECHNIC RELAY The invention relates to pyrotechnic relays and more particularly to a flexible pyrotechnic relay for igniting a receptor explosive charge located remote from an initiating explosive charge without the use of a pyrocore or detonating cord.

It is well known in the art that a pyrotechnic signal may be transmitted over a distance by pyrocores or detonating cords comprising a round, flexible sheath containing a continuous core of explosive material. It is also a known characteristic of explosive charges that the shock and/or flame generated by detonation of such a charge can detonate a separate charge spaced therefrom.

My present invention provides a device for the relay of a pyrotechnic signal without the use of a continuous core of explosive material for propagating the signal.

A feature of my invention is the provision of explosive relay charges spaced along the length of a tube between initiating and receptor charges located at the respective ends of the tube. The tube is effective to retain the explosive shock and flame effects of detonation of the initiating charge and to channel such effects to the adjacent explosive relay charge for detonation of that charge. The other explosive relay charges are successively detonated in the same manner. The last such charge detonates the receptor charge, thereby propagating the explosive signal from the initiating charge to the receptor charge.

A further feature of my invention is the provision of a flexible tube including a sheathed wound wire annor in which explosive charges are spaced to relay a pyrotechnic signal along the path defined by the flexible tube. The flexible tube retains the explosive shock and flame effects of detonation of the respective charges and channels these effects from one charge to the next charge.

According to the invention a flexible tube has at one end an initiating charge and at the other end thereof a receptor charge. In order to relay the pyrotechnic signal resulting from detonation of the initiating charge to the receptor charge, a plurality of relay explosive charges are spaced along the interior of the flexible tube between the initiating charge and the receptor charge. These relay charges are so spaced that the explosive shock and/or flame effects of detonation of the initiating primer are channeled through the tube to the adjacent relay charge to detonate this charge. The suc-' cessive relay charges are then likewise detonated, and the last relay charge detonates the receptor charge. In this manner the pyrotechnic signal is relayed through the flexible tube from the initiating charge to the receptor charge. The flexible tube includes a spiral wound wire armor sheathed with plastic or similar flexible material.

Other features, objects, and advantages of the invention become apparent upon consideration of the following specification and the drawings in which:

FIG. 1 is a view of a pyrotechnic relay device according to the invention having parts broken away; and

FIG. 2 is an enlarged view of a portion of FIG. I having parts broken away.

Referring now to FIG. 1 a flexible tube 8 has fittings 10 and 12 crimped to the respective ends thereof. As best seen in FIG. 2, the flexible tube 8 includes a spiralwound wire annor l4 sheathed in plastic or a similar flexible material l6.

A known initiating charge or percussion primer 20 is mounted in the end of a bore 22 provided in fitting 10. A known receptor charge or flame sensitive primer 24 is mounted in the end of a bore 26 in fitting 12. The flexible tube 10 defines a passage 18 which, in cooperation with the bores 22 and 26, provides a path between the initiating charge 20 and receptor charge 24. Pelletshaped explosive relay charges 28 and 30 of flame and- /or shock sensitive explosive material are mounted within the flexible tube 10 and spaced at such intervals between initiating charge 20 and receptor charge 24 as to propagate the explosive signal through the tube. r The initiating charge 20 can be detonated by a firing assembly 32 such as the sensor shown in Ser. No. 32,090, Prachar, filed Apr. 27, 1970 and assigned to the assignee of this invention. Firing assembly 32 includes a weight 34 slidably supported on guide 36 and an operator 38 slidably supported within the guide 36. Circumferentially spaced balls 40 fit within apertures 42 of guide 36 and engage shoulder 44 of operator 38 and wall 54 of weight 34 to hold operator 38 against movement under the bias of spring 46. Springs 48 and 50 exert axial bias, resisting movement of weight 34 in the respective axial directions. Upon movement by inertia of weight 34, wall 54 moves out of engagement with balls 40 and spring 46 drives firing pin 52 mounted on operator 38 into the initiating charge 20. Reference may be had to Ser. No. 32,090 for a more detailed description of the firing assembly 32, it being understood that the divers primer firing methods known to those skilled in the art may be used in the alternative.

Detonation of initiating charge 20 generates explosive shock and flame effects which are channeled through bore 22 into the flexible tube 10. The flexible tube 10 is sufficiently explosion impervious to retain and channel these explosive effects along a winding path to the relay charge 28. These explosive effects result in the detonation of relay charge 28 which in turn produces explosive effects which are communicated through flexible tube 10 to relay charge 30. The resulting detonation of relay charge 30 in turn produces explosive effects which detonate receptor charge 24. Thus, it may be seen that the pyrotechnic signal is propagated over a path of considerable distance by the detonation of spaced explosive charges mounted within a flexible tube. It is further noted that the explosive effects of the respective detonations will traverse a winding path between the initiating and receptor charges as defined by the flexible tube 10. The fitting 14 can of course be connected to any device which is actuated by detonation of receptor charge 24.

It will be understood that the respective explosive charges may be selected from the many commercially available explosive charges well known in the art. I have practiced the invention using a commercially available tube with a commercially available percussion primer of the type used in ammunition connected to one end of the tube and serving as the initiating charge. For the relay and receptor charges, I have used lead styphanite pellets of .8 grain spaced at six inch intervals along the length of the tube.

It will be further understood that by balancing such factors as the type of explosive charge employed, the distance between the adjacent relay charges, the size of the explosive charges and the construction of the flexible relay tube, the invention may be adapted for a multitude of applications as well as optimized for cost and reliability.

What is claimed is:

l. A pyrotechnic relay comprising an elongated flexible tubular means defining a passage and effective to retain the explosive effects of detonation of an explosive charge located therein, an initiating explosive charge mounted at one end of the tubular means, a receptor charge mounted at the other end of the tubular means, and at least one explosive relay charge mounted in the tubular means, the explosive relay charge being spaced from and independent of the initiating and receptor charges so that shock and thermal effects of detonation of the initiating charge channeled through the passage defined by the flexible tubular means detonates the relay charge which in turn detonates the receptor charge whereby an explosive signal is relayed through the flexible tubular means.

2. A device for transmitting an explosive signal comprising a flexible tube, a first explosive charge at one end of the tube, means actuatable to detonate the first explosive charge, a second explosive charge at the other end of the flexible tube and effective when detonated to actuate a system associated therewith, and a plurality of explosive charges serially spaced along the length of the flexible tube and independent of the first and second charges to propagate the explosive signal resulting from detonation of the first charge through the flexible tube by the shock and thermal effects of the progressive detonation of the spaced charges, the flexible tube being effective to contain the effects of detonation of the respective explosive charges.

3. A device for detonating a receptor explosive charge located remotely from a firing pin and comprising elongated flexible tubular means extending between the firing pin and the explosive charge, an initiating explosive primer mounted in the end of the elongated tubular means adjacent the firing pin and when detonated by actuation of the firing pin generating shock and thermal effects which are channeled through the elongated flexible tubular means, and a plurality of relay explosive charges serially spaced along the length of the elongated flexible tubular means between the initiating charge and the receptor charge and independent thereof to relay the explosive signal through the elongated flexible tubular means by the progressive detonation of the charges by the explosive effects generated by detonation of the preceding charges.

4. A pyrotechnic relay comprising a flexible tube including a spiral-wound wire armor encased in a flexible sheath effective to prevent escape of the shock and thermal effects of detonation of an explosive charge therein and a plurality of explosive charges serially spaced along the length of the flexible tube, the shock and thermal effect of detonation of one of the charges detonating the adjacent charge to relay an explosive signal through the flexible tube. 

1. A pyrotechnic relay comprising an elongated flexible tubular means defining a passage and effective to retain the explosive effects of detonation of an explosive charge located therein, an initiating explosive charge mounted at one end of the tubular means, a receptor charge mounted at the other end of the tubular means, and at least one explosive relay charge mounted in the tubular means, the explosive relay charge being spaced from and independent of the initiating and receptor charges so that shock and thermal effects of detonation of the initiating charge channeled through the passage defined by the flexible tubular means detonates the relay charge which in turn detonates the receptor charge whereby an explosive signal is relayed through the flexible tubular means.
 2. A device for transmitting an explosive signal comprising a flexible tube, a first explosive charge at one end of the tube, means actuatable to detonate the first explosive charge, a second explosive charge at the other end of the flexible tube and effective when detonated to actuate a system associated therewith, and a plurality of explosive charges serially spaced along the length of the flexible tube and independent of the first and second charges to propagate the explosive signal resulting from detonation of the first charge through the flexible tube by the shock and thermal effects of the progressive detonation of the spaced charges, the flexible tube being effective to contain the effects of detonation of the respective explosive charges.
 3. A device for detonating a receptor explosive charge located remotely from a firing pin and comprising elongated flexible tubular means extending between the firing pin and the explosive charge, an initiating explosive primer mounted in the end of the elongated tubular means adjacent the firing pin and when detonated by actuation of the firing pin generating shock and thermal effects which are channeled through the elongated flexible tubular means, and a plurality of relay explosive charges serially spaced along the length of the elongated flexible tubular means between the initiating charge and the receptor charge and independent thereof to relay the explosive signal through the elongated flexible tubular means by the progressive detonation of the charges by the explosive effects generated by detonation of the preceding charges.
 4. A pyrotechnic relay comprising a flexible tube including a spiral-wound wire armor encased in a flexible sheath effective to prevent escape of the shock and thermal effects of detonation of an explosive charge therein and a plurality of explosive charges serially spaced along the length of the flexible tube, the shock and thermal effect of detonation of one of the charges detonating the adjacent charge to relay an explosive signal through the flexible tube. 